1. Field of the Invention
This invention relates to a paper machine covering such as a mesh, in particular forming mesh.
2. Description of the Related Art
Requirements of many different types are imposed on paper machine meshes. For example, the paper side of the mesh facing the paper, in particular for the production of graphic papers, has to have a finely structured surface with the fewest possible marking points, the latter often being formed by so-called bonding diagonals. To achieve the longest possible life, on the other hand, the running side of the covering must have a rough structure with a large wearing volume in order to protect the force-absorbing fibers which are aligned in the machine direction.
To meet these requirements, coverings were developed in the past with a paper-side fabric and a running-side fabric, the two being connected together by way of tie threads.
From EP 1 294 981 there is known a forming mesh, for example, which has a paper-side fabric constructed as a linen bond and on which, in each running-side repeat in the warp direction, two intersections of the tie threads are formed when switching between their weaving with the paper-side and the running-side fabrics. In the case of the linen bond, the warp lifts are arranged on diagonals running parallel to each other, thus resulting in increased marking of the paper formed on such a fabric.
What is needed in the art is an improved paper machine covering such as a mesh with a reduced tendency to marking, on which the paper-side upper fabric layer and the running-side lower fabric layer are firmly connected to each other.